Several treatments have been developed to deliver therapeutic agents to a subject to treat an illness or a condition or for pain management. In most instances these therapeutic agents are delivered through a controlled or sustained release mechanism. Some systems to deliver sustained release doses of a therapeutic agent to a subject use biodegradable materials, such as polymeric matrices, containing the therapeutic agent. The matrices may be composed of biodegradable microparticles or microcarriers containing the therapeutic agent. As the microparticles or microcarriers degrade within a biological environment, they release the therapeutic agent at a controlled rate. One suitable biodegradable polymer is poly(lactic-co-glycolic acid) (PLGA). However, PLGA typically has a short degradation time and the time release of the therapeutic agents from a matrix formed with the PLGA is not readily tunable over a broad range. Additionally, PLGA degrades to form a high concentration of low molecular weight, acidic species. This interferes with the PLGA polymer matrices' biocompatibility and compatibility with therapeutic agents, as many are acid-senditive. Another drawback to PLGA polymer matrices is that they cannot be tuned for their mechanical properties such as degree of crystallinity or glass transition temperature over a substantial range. This limits their ability to tune retention and mechanical compatibility with different tissues within a subject. Lastly, PLGA is not soluble in highly biocompatible alcohol solvents, such as ethanol, requiring stronger organic solvents which can have less tissue compatibility.